bpo-32101: Add sys.flags.dev_mode flag

Rename also the "Developer mode" to the "Development mode".
python · vstinner · Nov 30, 2017 · Nov 28, 2017 · Nov 28, 2017 · Nov 29, 2017
commit 4c3e538f19ab9678c3a3163d86cff13ade54f0d9
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
@@ -334,6 +334,7 @@ always available.
    :const:`bytes_warning`        :option:`-b`
    :const:`quiet`                :option:`-q`
    :const:`hash_randomization`   :option:`-R`
+   :const:`dev_mode`             :option:`-X` ``dev``
    ============================= =============================
 
    .. versionchanged:: 3.2
@@ -345,6 +346,9 @@ always available.
    .. versionchanged:: 3.3
       Removed obsolete ``division_warning`` attribute.
 
+   .. versionchanged:: 3.7
+      Added ``dev_mode`` attribute for the new :option:`-X` ``dev`` flag.
+
 
 .. data:: float_info
 

diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
@@ -411,7 +411,7 @@ Miscellaneous options
      nested imports).  Note that its output may be broken in multi-threaded
      application.  Typical usage is ``python3 -X importtime -c 'import
      asyncio'``.  See also :envvar:`PYTHONPROFILEIMPORTTIME`.
-   * ``-X dev``: enable CPython's "developer mode", introducing additional
+   * ``-X dev``: enable CPython's "development mode", introducing additional
      runtime checks which are too expensive to be enabled by default. It should
      not be more verbose than the default if the code is correct: new warnings
      are only emitted when an issue is detected. Effect of the developer mode:

diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst
@@ -185,10 +185,10 @@ resolution on Linux and Windows.
        PEP written and implemented by Victor Stinner
 
 
-New Developer Mode: -X dev
---------------------------
+New Development Mode: -X dev
+----------------------------
 
-Add a new "developer mode": ``-X dev`` command line option to enable debug
+Add a new "development mode": ``-X dev`` command line option to enable debug
 checks at runtime.
 
 In short, ``python3 -X dev ...`` behaves as ``PYTHONMALLOC=debug python3 -W
@@ -371,6 +371,11 @@ string
 expression pattern for braced placeholders and non-braced placeholders
 separately.  (Contributed by Barry Warsaw in :issue:`1198569`.)
 
+sys
+---
+
+Added :attr:`sys.flags.dev_mode` flag for the new development mode.
+
 time
 ----
 

diff --git a/Lib/asyncio/coroutines.py b/Lib/asyncio/coroutines.py
@@ -31,7 +31,7 @@ def _is_debug_mode():
     # when _DEBUG is true.
     debug = (not sys.flags.ignore_environment and
              bool(os.environ.get('PYTHONASYNCIODEBUG')))
-    if hasattr(sys, '_xoptions') and 'dev' in sys._xoptions:
+    if sys.flags.dev_mode:
         debug = True
     return debug
 

diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
@@ -508,14 +508,18 @@ def test_sys_flags_set(self):
             with self.subTest(envar_value=value):
                 assert_python_ok('-c', code, **env_vars)
 
-    def run_xdev(self, *args, check_exitcode=True):
+    def run_xdev(self, *args, check_exitcode=True, xdev=True):
         env = dict(os.environ)
         env.pop('PYTHONWARNINGS', None)
+        env.pop('PYTHONDEVMODE', None)
         # Force malloc() to disable the debug hooks which are enabled
         # by default for Python compiled in debug mode
         env['PYTHONMALLOC'] = 'malloc'
 
-        args = (sys.executable, '-X', 'dev', *args)
+        if xdev:
+            args = (sys.executable, '-X', 'dev', *args)
+        else:
+            args = (sys.executable, *args)
         proc = subprocess.run(args,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.STDOUT,
@@ -526,6 +530,14 @@ def run_xdev(self, *args, check_exitcode=True):
         return proc.stdout.rstrip()
 
     def test_xdev(self):
+        # sys.flags.dev_mode
+        code = "import sys; print(sys.flags.dev_mode)"
+        out = self.run_xdev("-c", code, xdev=False)
+        self.assertEqual(out, "False")
+        out = self.run_xdev("-c", code)
+        self.assertEqual(out, "True")
+
+        # Warnings
         code = ("import sys, warnings; "
                 "print(' '.join('%s::%s' % (f[0], f[2].__name__) "
                                 "for f in warnings.filters))")
@@ -555,6 +567,7 @@ def test_xdev(self):
                          "default::ResourceWarning "
                          "default::Warning")
 
+        # Memory allocator debug hooks
         try:
             import _testcapi
         except ImportError:
@@ -569,6 +582,7 @@ def test_xdev(self):
                 alloc_name = "malloc_debug"
             self.assertEqual(out, alloc_name)
 
+        # Faulthandler
         try:
             import faulthandler
         except ImportError:

diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
@@ -526,10 +526,12 @@ def test_sys_flags(self):
         attrs = ("debug",
                  "inspect", "interactive", "optimize", "dont_write_bytecode",
                  "no_user_site", "no_site", "ignore_environment", "verbose",
-                 "bytes_warning", "quiet", "hash_randomization", "isolated")
+                 "bytes_warning", "quiet", "hash_randomization", "isolated",
+                 "dev_mode")
         for attr in attrs:
             self.assertTrue(hasattr(sys.flags, attr), attr)
-            self.assertEqual(type(getattr(sys.flags, attr)), int, attr)
+            attr_type = bool if attr == "dev_mode" else int
+            self.assertEqual(type(getattr(sys.flags, attr)), attr_type, attr)
         self.assertTrue(repr(sys.flags))
         self.assertEqual(len(sys.flags), len(attrs))
 

diff --git a/Misc/NEWS.d/next/Library/2017-11-29-00-42-47.bpo-321010.-axD5l.rst b/Misc/NEWS.d/next/Library/2017-11-29-00-42-47.bpo-321010.-axD5l.rst
@@ -0,0 +1 @@
+Add :attr:`sys.flags.dev_mode` flag
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
@@ -1814,21 +1814,23 @@ static PyStructSequence_Field flags_fields[] = {
     {"quiet",                   "-q"},
     {"hash_randomization",      "-R"},
     {"isolated",                "-I"},
+    {"dev_mode",                "-X dev"},
     {0}
 };
 
 static PyStructSequence_Desc flags_desc = {
     "sys.flags",        /* name */
     flags__doc__,       /* doc */
     flags_fields,       /* fields */
-    13
+    14
 };
 
 static PyObject*
 make_flags(void)
 {
     int pos = 0;
     PyObject *seq;
+    _PyCoreConfig *core_config = &_PyGILState_GetInterpreterStateUnsafe()->core_config;
 
     seq = PyStructSequence_New(&FlagsType);
     if (seq == NULL)
@@ -1853,6 +1855,7 @@ make_flags(void)
     SetFlag(Py_HashRandomizationFlag);
     SetFlag(Py_IsolatedFlag);
 #undef SetFlag
+    PyStructSequence_SET_ITEM(seq, pos++, PyBool_FromLong(core_config->dev_mode));
 
     if (PyErr_Occurred()) {
         Py_DECREF(seq);